Impulse sender



Dec. 24, 1940- H. P. BOSWAU IMPULSE SENDER Filed Jan. 29, 1957 4 Sheets-Sheet 1 w w w L 2 S M rl 0 .mnD "D1 6 5 2. 3 E 8. m m Hb u w: 2.3

i 7 8% mg o2 8 8. E 8. Q2 3 2. 2

H. P. BOSWAU IMPULSE SENDER Dec. 24, 1940.

4 Sheets-Sheet 2 NdE Inventor: Hans P. Boswau Filed Jan. 29, 1937 Dec. 24, 1940. H. P. BOSWAU IMPULSE SENDER Filed Jan. 29, 1937 4 Sheets-Sheet 3 Inventor Hans P. Boswau Dec. 24, 1940. )H. P. BOSWAU 2,225,680

IMPULSE SENDER Filed Jan. 29, 1937 4 Sheets-Sheet 4 FIG. 4

Inventor: Hans P. Boswau Patented Dec. 24, 1940 i v UNITED STATES PATENT, OFFICE,

IMBULSESENDER v Hans P. Boswau, Lorain, Ohio Application January 29, 1937, Serial No. 122,899 12 Claims. (01. 177-380) Theinvention relates to impulse senders of the type used by an operator in a semi-automatic telephone system for controlling the operation of automatic switches;

In known impulse senders of this type, which are usually based on the decimal system of numbers, the desired number is set up on groups of relays,'known as register relays, by the successive operation of so-called numerical keys in a key set. In order to reduce the number of register relays, it is customary to depart from the decimal system by using the register relays singly and in combination. Usually four register relays are provided for registering each digit of the desired number. In known impulse senders, the digit identified by the operated register relay or relays is translated back into the decimal system by suitable contact arrangements on the register relays, for the purpose of .sendingthe corresponding number of impulses. This arrangement requires a comparativelylarge number of contacts on the register relays. One object of the invention, therefore is to reduce the number of contacts on the register relays by eflecting the transmission of the proper number of impulses without first re-translating the digits stored in the register relays into the decimal system.

In known impulse senders, the register relays usually have one set of contacts for holding the relays operated after the numerical keys are released, and a second set of contacts for controlling the sending of impulses. Another object of the invention, therefore, is a further reduction in the number of contacts on the register relays by using the same contact both for holding 'a' relay operated and for controlling the sending of impulses, thereby reducing the number of contacts required on each register relay to one normally open contact.

Known impulse senders of the relay type are usually provided with one set of relays for shifting the control circuits from the key set from one group of register relays" to the next after each digit has been 'registered,and a second set of relays for shifting the sender control circuits from one group of register, relays to the next during the sending of impulses. Accordingly, another object of the invention is to combine the functions of these two separate sets of relays, so that the same relays effect the shifting from one register to the next, both during the registration of a number and during the transmission of impulses. In some embodiments of the present invention, a single relay per digit is sufiicient for this purpose.

The relay counting chains employed in known impulse senders of the relay type usually require 1 seven or eight relays for counting up to ten impulses. The problem of counting ten impulses requires the discrimination of twenty distinct conditions, via, ten so-called marking conditions for the ten impulses, nine so-called spacing conditions for the pauses between the im- 10 pulses, and one condition with all relays de-' energized when the counting chain is at rest. With ordinary relays, such as used in automatic telephone systems, which have a non-operated and an operated position, partially operated position, the total number of combinations obtainable with a given number of relays is equal to 2" where n is the number of relays. Accordingly, it is possible to obtain the twenty distinct conditions necessary for count- 20 mg ten impulses with not more than five relays in the counting chain, five relays giving 2 or 32 combinations. Four relays provide 24 or 16 combinations, which is not enough.

It is another object of the invention, based 25 on the foregoing, to reduce the number of relays required for counting ten impulses to the theoretical minimum, viz., five, without unduly increasing the number of contacts required on each of these five counting relays. I

In summing up, the general object of the invention is to provide an impulse sender accomplishing all the functions required of such senders with a materially smaller number of relays and relay contacts than pulse senders.

The invention is illustrated in the accompanying drawings, in which Fig. 1 shows one embodiment of the impulse sender control and counting circuits and Fig. 2, 3, and 4 show'several em- 40 bodiments of the associated register relays.

.The operators position with which the impulse sender is associated may be providedwith ten numerical keys/I00 to 19, Fig. 1, for selecting the ten digits of the decimal system, one correction key 113 for releasing all previously selected digits in the case of an error, and one start key H5. The impulse sender is engaged for the purpose of sending a number of external circuit means, not shown in detail, but indicated selective means are interposed between the posi- '55 but no intermediate 5 is customary in known im- 35 tion equipment and the impulse sender at the points indicated by the reference numbers H0, H6, and H1, in addition to the contact II4. These selective means form no part of the impulse sender and are therefore not shown.

In the following description, terms such as "winding 2I0, "break contact 2I5 or make contact 21 I shall be understood to mean winding of relay 2I0, break contact of relay 2I5," or "make contact of relay 2 I I, respectively.

Upon engagement of the impulse sender by the closure of contact II4, relay 2I0 operates from battery over winding 2i 0, break contact 2 I5, conductor I48, break contacts I30 and I26, contact I I4 and correction key I I3 to ground. The operation of relay 2I0 connects the four register relays 2| I, 2I2, 2I3, and 2I4, over the four conductors I4I, I40, I39, and I38, and through break contacts I30 to the numerical. keys,

preparatory to the registration ofthe first digit of the desired number. The operation of any one of these keys energizes one or more of the register relays 2I I to 2I4 the relay combination associated with each key being shown in the following table: I y Key 101 energizes relay 211 Key 102 energizes relay 212 and registers digit 2 Key 103 energizes relay 213 and registers digit 3 key 104 energizes relays 211 and 213 and registers digit 4 Key 105 energizes relays 212 and 213 and registers digit 5 Key 106 energizes relay 214 and registers digit 6 Key 107 energizes relays 211'and-214 and registers digit! Key 108 energizes relays 212 and 214 and registers digit 8 Key 109' energizes relays 212, 213, 214 and registers digit 9 Key energizes relays 211 and 212 and registers digit 0 Only the relay or relays which correspond to the operated key are energized, notwithstanding the fact that conductors I42, I43, I44, and I45 are allmultiplied together at contacts of relays I3I to I35 inclusive. This result is accomplished by the insertion of rectiflers 200, which prevent current flow in conductors I42, I43, I44, and I45 in a direction toward the register relays.

When a relay such as 2 is energized by the operation of the associated key, locking circuits are prepared for the operated relay over its own make. contacts, winding 2I5, conductor I41, break contact I26, contact H4, and key II3 to ground. While the numerical key is operated, relay 2I5 is short-circuited and cannot operate, but when the key is released, the short-circuit is removed, and as a result relay 2I5 operates in series with the operated register relay 2. The operation of relay 2I5 opens the circuit of relay 2I0 and in its stead operates relay 220, which connects the numerical keys to the register relays 22I to 224, associated with the second digit. g

The next operation of one of the numerical keys energizes one or more of the relays 22I to 224. When the operated key'is released, the energized register relay (or relays) is locked in series with relay 225, which operates, releasing reand registers digit 1 lay 220 and operating a relay similar to relay 220 in the register for the next digit, not shown. It will be evident that as many digits as desired may be registered in the described manner, a group of register relays similar to those shown for the first and second digits being provided for each additional digit. v

It will be noted that the locking circuit for relays 2i I to 2I5, 22 Ito 225 and for the correspond ing relays of additional digits is carried through key II3, so that any. number or part thereof, which may have been registered, can be wiped out by operating correction key II3.

After registering the desired number, which may or may not have the full number of digits for which registers are provided, the operator manipulates the start key II5, thereby closing a circuit for relay I30 from battery over resistance I53, key I I5, upper winding I30, conductor I50 to ground through make contacts 2I5, 225 and so 5 forth. It will be noted that the circuit for relay I30 is completed only if at least one digit has been registered, so that the operation of the start key II5 will have no effect on the impulse sender, unless it is preceded by the registration of a number.

Relay I30 closes a locking circuit for itself from battery over lower winding I30, upper and lower make contacts I30, conductor I50 to ground through make contacts 2I5, 225 and so forth. Relay I30 also provides a new locking circuit for the register relays 2i I to 2I5, 22I to 225, etc., from conductor I41 over upper and lower make contacts I30, conductor I50 and make contacts 2i 5, 225, etc., so that contact II4 may now be opened 20 or correction key II3 operated, without affecting the further operation of the sender.

The operation of relay I30 opens the connections from the numerical keys to the register relays, so that subsequent operations of these keys 25 will not change the number already registered. Where selective means are provided to switch the position equipment to another idle impulse sender as soon as the start key is operated, the four break contacts of relay I30 in conductors I38, I39, 30 I 40 and I may be omitted, in view of the fact that the selective means will disconnect the keys from conductors I38 to I4I at the point indicated by the reference number I I0.

As a further result of the operation of relay 35 I30, ground is removed from conductor I48 and the circuit of relay 220 or of the corresponding relay for the last digit of the registered number is opened and in its stead a circuit is closed for relay 2I0 of the first digit from battery over winding 40 2I0, make contact 2I5, conductor I49, upper and lower make contacts I30, and conductor I50 to ground through make contacts 2I5, 225, and so forth. Relay 2I0 connects register relays 2 to 2I4 of the first digit to conductors I42 to I45 for the purpose of controlling the number of impulses transmitted for the first digit, as described in detail below.

The operation of relay I30 also closes a circuit for relay I29 from battery over winding I 29, break contact I28, upper and lower make contacts I30, conductor I50 to ground through make contacts 2I5, 225, and so forth. Relay I29 operates, in turn energizing relay I31 from battery over upper winding I31, break contact I36, make contact I29, upper and lower make contacts I38, conductor I50 to ground through make contacts 2I5, 225, and so forth.

Relay I31 prepares a locking circuit for itself in series with the upper winding of relay I36. The latter winding. however, is short-circuited over ,make contact I29, so that relay I36 cannot operate as long as relay I29 is energized. The'operation of relay I31 also energizes relay I28 from ground over make contact I31, break contact I25, and winding I28 to battery. Relay I28 operates relay I21, which in turn energizes relay I25, over obvious circuits. Relay I26 opens the circuit of relay I28, causing the successive release of relays I28, I21, and I26, whereupon the cycle of operations is repeated. Thus relays I28, I21, and I28 constitute a relay interrupter, resistances I22, I23 and I24 or other suitable means being provided to delay the release of the interrupter relays for II aaaaoso the purpose of obtaining the required sending speed with the desired ratio, of make and break intervals.

The intermittent operation and release of relay I28 controls the counting chain consisting of the five relays I3I to I35. The first operation of a relay I 28 energizes relay I 3I from battery over winding I31, break contacts I32 and I33, make contacts I28 and I29, upper and lower make contact I30, conductor I50 to ground through make contacts 2I5, 225, and so forth. The first release of relay I28 closes a holding circuit for relay I3I in series with the upper winding of relay I32,

l and I32, make contact I3I, break contact I28 toground over the previously described circuit. The second operation of relay I28 closes a holding circuit for relay I32 from battery over lower wind ing I32, make contact I32, break contact I33, make contact I28 and so forth to ground. At the same time, the holding circuit for windings I3I and I32 in series is opened at break contact I28, so that relay I3I releases. The second release of relay I28 energizes relay I 33 in series with relay I32 from battery over lower winding I32, upper winding I33, make contact I32, break contacts I3I and I28, and so forth to ground. The third operation of relay I28 opens this circuit, causing the release of relay I32, while relay I33 is locked from battery over lower winding I33, make contacts I33 and I28, and so forth to ground.- At the same time relay I 34 is energized in parallel with lower winding I33 over upper winding I34, break contact I35 and resistance I to battery. Upon the third release of relay I28,'the locking circuit of relay 133 is opened, thereby releasing relay I33, while relay I 36 looks from battery over lower winding I33, make contact I34, break contact I35,

make contact I29, upper and lower make contacts I33, conductor I53 to ground through make contacts 2 I5, 223, and so forth.

The fourth, fifth and sixth operation and release of relay I23 control relays I3I, I 32 and I33 as described for the first three steps. In addition,

over make contact I33 in parallel with upper windin I 33. Relay I35 locks up from battery over resistance I25, make contact I35, lower winding'I 35, make contact I29, and so forth to ground. Moreover, relay I35 transfers the above described locking circuit of relay I34, from break contact I35 to make contact I35 and breakcontact I3I.

The seventh operation of relay I 28 energizes relay I3I as described for the first impulse. With relay I31, operated, relay I34 looks over its own make contact and make contacts I35, I3I, I28, and so forth to ground. Upon the seventh release 60 of relay I 28, relay I 32 operates in series with relay I3I as described above. With relays I3I, I32 and I35 energized and relay I28 released, ground is disconnected from the locking circuit of relay I34, causing it to release.

I 3|, I 32 and I33 function as described for the which operates, from battery over windings I'3I- the fifth release of relay I28 energizes relay I35 During the eighth and ninth impulses, relays successive repetitions. For a clearer understanding of the operation of the counting chain, the various relays which are operated during each of the ten impulses are listed in the table below.

* Relaysopcrated during Relayso rated be- Impulse impulses tween i ipulscs 131 132 134 5th i 132 134 132 133 134 135 134 135 7th 131 134. 135 I 131132 135 8th 132 .l 35

Attention is invited to the fact that, although only live relays are used for counting ten impulses, not one of these relays has more than six contact springs in the counting circuit proper, one relay having only five springs, one relay four springs, and one relay three springs. The total number of contact springs in the counting circuit proper is only twenty-four, which is believed to be less than in any ten-step counting chain heretofore known.

While the countingchain is going through these steps with relay I31 energized, the externalimpulse circuit controlled by the sender and includ-' ing conductors I5] is interrupted once for every operation of relay I23, thus transmitting impulses over these conductors. Instead of breaking a normally closed circuit, as shown, the external impulse circuit may be closed for every operation of relay I28, or it may be arranged in any other suitable manner, depending upon the purpose to be served.

For descriptive purposes, it has been assumed in the foregoing description that relay I 29 remains energized while ten impulses are being transmitted. However, each time an impulse is transmitted, the original energizing circuit of relay I29 is replaced by a test circuit controlled by a group of register relays, and relay I29 may or may notremain energized for the. full number of ten impulses, depending on the digit registered. For this purpose, the circuit of relay I29 is transferred over make contacts I26, I 27, and I29 throughcontacts of the counting relays I3I to I35 to conductors I42, M3, I44 and I35, which are connected over make contacts of relays 2), 220, etc., to the register relays on which the digit being transmitted at the time is registered.

vThis transfer does not take'place until relay I 28 has operated relay I21, in order to insure that the counting relays controlled by relay I28 have assumed their new positions before the test is made. For a similar reason, the test circuit is transferred back to the original operating circuit of relay I29 as soon asrelay I28 releases, so that the changes in the counting chain caused by the release of relay I28 will have no eifect upon the test circuit;

The test is accomplished by providing a holding circuit for test relay I29 over contacts of the counting and register relays during .each test period until the desired number of impulses has been transmitted, whereupon relay I29 no longer the test period and I44, I43, and I42, which are open at the make contacts of relays 2I2, 2I3, and 2I4, while conductor I45, which is grounded through make contact 2, winding 2I5, etc., is disconnected from relay I29 by break contact I3I. As a result, relay I29 releases during the first impulse, stopping the sending of further impulses, as described hereinafter.

If the digit 2 has been registered, register relay 2I2 will be operated, while register relays 2H, 2I3 and 2I4 are tie-energized. In this case, relay I29 finds a holding circuit during the test period of the first impulse which extends from battery over winding I29, make contacts I29, I21, I 29, break contacts I32 and I35, conductor I44,

rectifier 260, make contacts 2H] and 2I2, winding 2I5, conductor I41, make contacts I30, conductor'lill, make contact 2l5 to ground. During the second test period, this circuit is opened by relay I32, so that relay I29 releases after two impulses have been sent.

periods.

first five test periods.

For the digit 3 register relay 2I3 will be operated while the other three register relays are de-energized. During the first and second test periods, relay I29 finds a holding circuit from battery over winding I29, make contacts I28, I21 and I29, break contacts I34 and I33, conductor I43, rectifier 200, make contacts 2! and 2I3,

winding 2I5, and so forth to ground. In the thirdtest period, this circuit is opened by break contacts I33 and I34, causing relay I29 to release.

The register relay combination for the digit 4 is relays 2H and 2I3 operated, providing the last described holding circuit 'over break contacts I33 and I34- during the first and second test In addition, another holding circuit is completed during the second test period over break contact I3I and make contacts 2H) and 2I I, this holding circuit also being effective during the third test period. When the fourth test period is reached, both holding circuits are opened by relays I3I and I34, thereby releasing relay I29.

When the register is set for the digit 5, relays 2I2 and 2I3 operated, relay I29 holds during the first test period over break contacts I32 and I35 and make contacts 2H] and 2I2, and also over break contacts I34 and I33 and make contacts 2H! and 2I3. The first mentioned circuit is also effective during the second test peirod, while the last mentioned circuit holds relay I29 during the third and fourth test periods. In the fifth test period, relays I32 and I34 are both operated, thus breaking both holding circuits for relay I23.

If the digit 6 has been registered, register relay 2I4 alone is operated, providing a holding circuit for relay I29 over break contacts I35 and I35and 'make contacts 2H] and 2I4 during the This holding circuit is broken during the sixth test owing to relay I35 being operated at this time. a

If the digit I has been registered, register relays 2I I and 2I4 are operated. In this case, theholding circuit for the first five test periods is the same as for six impulses. Moreover, an-

otherholding circuit over break contact I 3I and' by having relays I3I, I 34 and I35 operated.

For the digit 9, register relays 2I2 and 2I4 are energized, providing a holdinfl circuit over break contacts I35 and I38 and make contacts III! and 2I4 for the first five test periods, a second holding circuit over break contacts I32 and I35 and make contacts 2I0 and 2I2 during test periods 1, 3 and'4, and a third holding circuit effective during test periods 6 and '7 over make contacts I34, I35, 2I0, and 2I2. In test perlod 8, relays I32 and I35 are operated. while relay I34 is de-energized,, so that all three holding circuits are open.

When the register is set for the digit 9 by having relays 2I2, 2I3 and 2I4 operated, the holding circuit for test periods 1 to 5 is traced over break contacts I35 and I36 and made contacts 2III and 2I4. Another holding circuit over break con tacts I34 and I33 and make contacts 2H] and 2I3 is closed in test periods 1, 2 and 8, while break contacts I32 and I35 and make contacts 2H! and 2I2 complete an additional holding circuit for test periods 1, 3 and 4. During test periods 6 and I, relay I29 holds over make contacts I34, I35, 2"] and 2I2. When test period 9 is reached, relay I35 opens the holding circuits completed over make contacts 2I2 and 2I4, while relay I33 breaks the circuit extending over make contact 2I3.

I For the digit 0, corresponding to ten impulses, relays 2H and 2I2 are operated, closing a holding circuit for test periods 2, 3, 5, 6, 8 and 9 over break contact I3I and make contacts 2III and 2| I, another holding circuit for test periods 1, 3 and 4 over break contacts I32 and I35 and make contacts 2H] and 2I2, and athird holding circuit for test periods 6 and 7 over make contacts I34, I35, 2) and 2I2. All these holding circuits are open in the tenth test period, thus causing relay I29 to release.

It will be seen that each of the ten different register relay settings causes the release of relay I29 after the sender has transmitted the number of impulses which corresponds to the digit registered. The release of relay I29 opens the operating and holding circuits of all five counting relays I3I to I35, thereby restoring the counting chain to normal. A make contact I29 is included in the test circuit of relay I29 to prevent its immediate re-operation' during the last test period due to the re-closure of the test circuits by the release of the counting relays.

When relay I29 releases, the short-circuit across the upper winding of relay I36 is opened, allowing this relay to operate in series with the upper winding of relay I31. The operation of relay I36 shunts anyof the register relays 2 to -2I4 which may be operated, over resistance I2I,

conductor I46, make contact 2) and over the make contacts of the operated register relays. Resistance I2I, being a protective device customarily provided where relay contact springs are connected to battery, is of sufi'iciently low. value to reduce the current flowing in windings 2| I to 2I4 so much that these relays release.

While relay I36 is operated, relay 2I5 remains energized from battery over resistance I'll, make contact. I36, conductor I46, make contact 2III, winding 2 I5, and so forth to ground.

. When relay I28 releases at the end of the last of register relays 22I contact I28 I 29 releases.

next register, while preserving the identification test period, during which relay f I29 is released, a circuit isagain closed forre'lay I29 over break and make contacts I39 and 2I5. Relay I 29 operates, preparing the operating and holding circuits for the counting relays and energizing the lower windings of relay I36 and I31 from ground over make contacts 2I5, I30, I29, I36 and I31. The two windings of relay I31 are .so connected as to oppose each other, with the result that relay I31 releases, while relay I36 remains energized over its lower winding.

In order to provide the necessary time inter val between" successive series of impulses, the sender now takes six steps; that is, the relay interrupter, including relay I28, continues to operate, but without breaking the external impulse circuit, relay I31 being de-energized at this time. The holding circuit for relay I 29 during the first five test periods is traced over break contact I35 and make contact I36. In the sixth test period. relay I35 is operated, so that'relay As a result, the counting relays and relay I36 are de-energized, the latter relay opening the previously described circuit for relay 2I5. The release of relay 2I5 de-energizes relay 2 ID and closes a circuit for relay 220,.which connects the register relays for the second digit to conductors I42 to I45 in preparation for the transmission of impulses in accordance with the second digit.

When relay I29 releases at the end of the last described test period, relay I29 operates again as explained above, and the impulse sender from now on functions exactly the same asfor the first digit, except that relay 220 being operated instead of relay 2III, the sender is under control to 224 of the second digit. After the second digit has been transmitted, relays 22I to 224 are released as described above for the first digit, whereupon the sender takes six steps to provide the time interval between digits. At the end of this interval relay 225 releases, shifting the control to the register relays for the next digit, and this action continues until the sender has transmitted all digits that have been registered. When the last one of the relays 2| 5, 225, and similar relays for the succeeding digits is released, ground is removed 1 fromconductor I50, thereby restoring theimpulse sender to normal. The circuit through contact I14, over which the held open by a break contact of relay I26, which is the last relay to release, in order to insure the complete release of the sender, even though contact H4 is still closed at the time.

The register circuit shown in Fig. 2 has been worked out with the aim to reduce the number of register contacts to a minimum, but not to use the smallest possible number of relays. In this circuit, the register for one digit requires only twenty-six contact'sprlngs, of which the two springs constituting the lowest make contact of relays 255, 225, etc., could be eliminated by substituting for them a common makecontact on a It is believed that no further reducr relay with its winding placed in series with con-- ductor I41.

tion in the number of contacts is possible when '1 using ordinary telephone relay v,

As far as the nnmmum number of relays necessary for a register is concerned, the answer will be found by determining the'requirednumber of re lay combinations. Ten distinct relay combinations are necessary 'for registering the, desired numeral. completed,

When the registration ofv the digit is sender may be engaged, is'

the key circuits must be shifted to the of the registered numeral, so that ten additional relay combinations are needed. The shift from tion will be sufiicient. Adding one relay combination for the normal condition with all relays released, it will be seen that twenty-two different combinations are necessary, which can be obtained with five relays. I

The register circuit shown in Fig. 2 uses six relays per digit. In order to reduce the number of relays to the theoretical minimum, relays 2I9, 220, etc., can be eliminated, as shown in Fig. 3, by the use of additional contacts on relays 3I5, 325, etc. In Fig. 2 the winding of relay 2! is controlled over the two make and break contacts shown immediately below winding 2I5. The upper one of these contacts controls relay 2I9 during the registering period, whereas the lower one used during the transmission period. In Fig. 3 -wo make and break contacts of relay 3I5 in a similar circuit are substituted for each of the four right-hand make contacts of relay 2I0. The lefthand make contact of relay 2IIl is replaced by a. single make and break contact of relay 3I5, as this contact is used only during the transmission of impulses, but not while a number is being registered. Relay 30I is added in order to close the circuits from conductors I 42 to I45 to the contacts on relays 3I5, 325, etc., which come into play when the sender is transmitting impulses. Relay 3III operatesover a make contact of relayI30 after the start key I I is operated. I

The register circuit shown in Fig. 3 uses the smallest possible number of relays and requires only a single make contact on four'of the register relays, but the fifth register relay must be provided with a comparatively large number of contact springs. In the circuit arrangement shown in Fig. 4 the number of contact springs on the fif-th register relay is reduced by transferring some of the functions peformed' by it during the transmission period to additional contacts on the other four register relays. In this case the sendercontrol circuit is switched during the trans-- mission period from one digit to the next by a single make, and break contact of relay 4| 5, makj ing it impossible to connect conductors I42 to I45 in multiple to the register relays of all digits, as

. in Fig. 2. Instead, it is necessary to open conductors I42 to I45 between successive digit regis ters by break contacts of relays III to M4, 42I to 424, etc., in order to avoid undesired circuit paths.

Assuming, for example, that numerals 1 and 4 were registered for the first and second digit, respectively, and that no break. vided on relays I and .423 to conductorv I43,

relay 5 for four make and break contacts. of re- In this embodiment, the holding circuit or test circuit for relay I29. does not. includethe locking contacts of the register relays, but is comcontacts were pro- I to 4 I4, etc., a, circuit wouldbe closed from conductor I 45,'which is grounded during the transmission of the :firstdigit, over make contacts which should be open for numeral 1,,thus causingthe impulse sender to transmit four impulses inpleted through separate contacts on these relays,

tacts. Fig. 4 shows a circuit with a minimum of relays and a numberof contacts intermediate between Figs. 2 and 3.

While my improved sender has been described herein as being used by an operator in a semiautomatic telephone system, it will be understood that it is adapted for use in other types of systems, such as stock quotation systems, remote control systems, fire alarm systems, etc., either in the form shown or with modifications appropriate to the associated equipment. I do not, therefore, desire to be limited to the exact disclosure herein, but desire to include and have protected by Letters Patent all forms and modifications of my invention which come within the scope of the appended claims.

I claim:

1. In a register sender, digit registering relays, each having a pair of locking contacts, circuit means for locking any energized relay through its locking contacts, a counting device, and a test circuit including said locking contacts for stopping said device.

2. In a register sender, digit registering relays, each'having a single pair-of contacts, means for setting said relays to register digits,-a sender controlled by said relays,'lockingcircuits for said re lays including said contacts, and circuits also including said contacts for stopping said sender 3. In a register sender, a set of keys, a group of register relays, a group of conductors over which said relays are set from said keys to register-digits, a sender, a group of branch conductors extending to said sender which together with the conductors of said first group enable the sender to be controlled by said relays, said branch conductors being connected'together at the sender at the time said register relays are being set, and

rectifiers inserted in said branch conductors to effectively isolate the conductors of said first group .during'the setting of said relays.

4. In a register sender, a group of register relays, a group of individual control conductors over which said relays are set, a sender, a group of branch conductors over which said relays control said sender, said branch conductors being connected together at the sender at the time said register relays are being set, and a rectifier ineach branch conductor to prevent a setting potential applied to one of said control conductors from causing a current flow over two branch conductors in series and bring about a false setting of said register relays.

'5. In a register sender, a group of register relays, a sender, individual conductors leading from said relays, respectively, to a common test circuit at said sender, a rectifier inserted in each of said conductors to enable a portion thereof adjacent the associated relay to be .usedfor setting the relay to register a digit, said rectifiers being efiecsaid test relay, and means included in said-inter- 5' rupter device for substituting said test circuit for said energizing circuit each time an impulse is t, y

transmitted. 7. In a register sender, a register, a counting device, a test circuit including said register and i0 counting device, a relay for transmitting impulses, means for operating the counting device to change the test circuit each time. an impulse is transmitted, a test relay, and means for temporarily connecting said test relay to said test circuit each time after the circuit has been changed.

8. In a register sender, a register, a counting device, a test circuit including said register and counting device, a sender for transmitting impulses, said sender including means for operating said counting device each time an impulse is transmitted to open the test circuit when the number of impulses transmitted corresponds to the setting of said register, means including a test relay for stopping the sending of impulses by deenerg izing, and means whereby the continued energization of said test relay is made dependent upon the continuity of said test circuit for an interval during the transmission of each impulse.

9. In a register sender, a plurality of relay registers, a group of setting conductors, means including transfer relays for associating said conductors with said registers successively, means responsive to setting of said registers over said conductors for energizing said transfer relays successively, a sender, sender control conductors associated with the first of said registers after the same have been set, means controlled by said sender for restoring. said registers successively and also for restoring said transfer relays successively, contacts on the register relays for transferring said sender control conductors from one register to the next as the registers are restored, and contacts on the transfer relays whereby the sender is able to control the restoration of said registers and transfer relays as set forth.

10.".[n a register sender, a relay register, means for setting said register by energizing one or more relays thereof, a locking circuit for the energized relays including a relay common to therelays of the register, a sender, a group of sender control conductors comprising a conductor individual to each register relay, and circuit means for placing a potential on the control conductor corresponding to any operated register relay, said last means including a contact on the operated relay and a contact on the said common relay.

11. In a register sender, a relay register, means for setting said register by energizing one or more relays thereof, a sender, a group of sender control conductors comprising a conductor individual to each register relay, means including a front contact on each register relay for placing a control potential on the associated control conductor, a back contact on each register relay through which the associated control conductor is extended to the corresponding relay in a second register, the register relays in the second register also having front contacts for placing control potentials on said conductors, and means for preventing an energized relay in the second register from placing a control potential on the associated conductor while the corresponding relay in the first register is energized.

12. In a register sender, a pluralityoi relay I atthe first register that the potential placed thereon after the first digit is transmitted is effective to shunt down all operated register relays and hold the transfer relay, the transfer relay being released when the potential is removed, and

contacts on each transfer relay except the last for extending said conductor to the next register.

HANS P. BOSWAU. 

